Due to the recent gradual decrease in fossil energy, and consequently the growing demand for energy-saving products, the light-emitting diode (LED) technology has made significant progress.
Under conditions of instability of the oil price, many countries around the world have actively engaged in development of energy-saving products, and the application of light-emitting diodes in energy-saving bulbs is a product of this trend.
In addition, with the advancement of light-emitting diode technology, applications of white or other color (blue, for example) light-emitting diodes get more widespread.
As the light-emitting diode technology matures over time, there are more and more applicable areas. The applications of light-emitting diodes to lighting includes residential areas: wall lamps, nightlights (the earliest field for using light-emitting diode as light source due to low requirement for brightness) auxiliary lights, garden lights, reading lights; utility areas: emergency lights, hospital bed lights; business areas: spotlights, downlights, light bars; outdoor areas: building exteriors, solar lights; and light shows, etc.
In addition to advantages of light-emitting diodes such as low power consumption, mercury free, long life, and low carbon dioxide emissions, the environmental policy of governments around the world banning the use of mercury has also encouraged researchers to delve into R&D and application of white light-emitting diodes. While the global trend of environmental protection rises, the light-emitting diode regarded as a green light source is in line with global mainstream trends. As pointed out previously, it has been widely used in 3C product indicators and display devices; also with the increase in production yield of light-emitting diodes, unit manufacturing costs have been greatly reduced, therefore demand for light-emitting diodes keeps increasing.
As described above, the development of high-brightness light-emitting diodes has become the focus of research and development of companies around the world at this moment; however, current light-emitting diodes are still flawed in application design, so that it is hard for the luminous efficiency to be optimal.
In practical applications, light-emitting diodes are often combined as light-emitting diode array modules, which arrange a large number of light-emitting diode chips on the substrate and obtain a better light-emitting effect by taking advantage of quantity. However, such a way of arranging light-emitting diode chips, in addition to problems of cooling that occur most frequently, how to further enhance the light-output efficiency is the subject that we should face and think about in this field.
In the prior technologies, as shown in FIG. 1, light-emitting diode chips are arranged side by side on a large substrate, and connected to one another by wire bonding to form a light-emitting matrix. FIG. 1 includes a substrate 10 and a plurality of light-emitting diode chips 20; the light-emitting diode chips 20 align neatly in the form of a matrix. In this arrangement, except the top surfaces of the light-emitting diode chips 20 and two side walls of the chips at four corners, light emitting from the rest of side walls of the light-emitting diode chips 20 are mutually shielded by adjacent chip; as a result, light output from sides around the chip is undoubtedly a waste and lighting efficiency of the light-emitting matrix is low.